THE IMPORTANCE OF DIAGNOSING MYCOBACTERIUM TUBERCULOSIS BY REAL-TIME PCR (POLYMERASE CHAIN REACTION IN REAL TIME) COMPARED TO THE DIAGNOSTIC METHODS ADOPTED IN THE CLINICAL LABORATORY

*Khldoun Salah Aslan

ABSTRACT

Background: Tuberculosis remains a serious public health problem worldwide. Ziehl-Neelsen stained smear and culture on LJ media are conventional methods used for the diagnosis of Mycobacterium tuberculosis in most developing countries. PCR for the diagnosis of tuberculosis is not evaluated in developing countries. The Aim of the study: To compare the ability of Real time PCR to diagnose MTB in pulmonary and extra-pulmonary samples, and compare it with the results of ZN and LJ. Materials and Methods: Samples obtained from 96 patients of suspected TB (pulmonary and extra-pulmonary) were processed for detection of MTB by ZN smear examination, LJ medium culture and Real time PCR test. Results: The sensitivity of Real time PCR was 97,8% compared to 17, 4% for smear microscopy and 100% for LJ culture. Percentage of TB detection using Real time PCR in pulmonary and extra-pulmonary samples was 96% and 100% respectively. The mean detection time for MTB was 6 weeks by LJ medium culture, less than one day by PCR and 4 days by ZN for 96 samples. Conclusions: PCR is a rapid and sensitive method for the early diagnosis of pulmonary and extra- pulmonary tuberculosis.

Keywords: Mycobacterium Tuberculosis, Real time PCR, ZN staining, LJ medium culture, pulmonary TB, extra pulmonary TB.